The Animal Behavior Core will provide services, technical assistance and training needed for behavioral testing of mice and rats to satisfy the experimental aims of the investigators within the Research Components of the ACTG. A primary goal of the Animal Behavior Core is to standardize the methods and the analyses for alcohol-related behavioral testing for mice and rats. Core personnel will conduct all homecage drinking studies in mice and rats, and other ethanol-related behavioral tests, as required by the Research Components. The core will instruct research personnel in other behavioral procedures as needed. In addition, the Core will directly compare the rat operant self-administration procedures currently in use by Center Investigators. By conducting a considerable proportion of the behavioral testing within the Core, we ensure that the procedures are performed, and the data are analyzed, in a consistent manner, allowing for maximal comparability of the effects of different experimental manipulations across center projects. This model of centralized behavioral testing by the Animal Behavior Core worked extraordinarily well in the first funding period, allowing for smooth, efficient completion of many behavioral studies. The overall goal of the Animal Behavior Core is to assist Research Components in experiments that test hypotheses regarding the role of novel signaling molecules in alcohol drinking.